 var flag = false;  
 function DrawImage(ImgD, iwidth, iheight) {   

//参数(图片,允许的宽度,允许的高度)   
var image = new Image();   
 image.src = ImgD.src;   
if (image.width > 0 && image.height > 0) {   
flag = true;   
if (image.width / image.height >= iwidth / iheight) {   
if (image.width > iwidth) {   
ImgD.width = iwidth;   
ImgD.height = (image.height * iwidth) / image.width;   
} else {   
 ImgD.width = image.width;   
 ImgD.height = image.height;   
 }   
// ImgD.alt = image.width + "×" + image.height;   
}   
 else {   
 if (image.height > iheight) {   
 ImgD.height = iheight;   
 ImgD.width = (image.width * iheight) / image.height;   
 } else {   
 ImgD.width = image.width;   
 ImgD.height = image.height;   
}   
//ImgD.alt = image.width + "×" + image.height;   
 }   
}   

}    

